A known elastic strip used in a membrane circuit board-based keyboard is disposed beneath outlet lines of the membrane circuit board; with a rebound force produced whenever the known elastic strip is squeezed, the outlet lines of the membrane circuit board are pressed against electrical connections of a printed circuit board, forming electrical connections. There are two types of known elastic strips in terms of structure, namely solid elastic strips and hollow elastic strips. However, when squeezed, both types of the elastic strips produce a rebound force that manifests an enduring linear increment. Referring to FIG. 1 which illustrates a rebound force generated during a squeezing process, while a membrane circuit board is pressed against a printed circuit board by means of a elastic strip. The rebound force generated by the elastic strip varies during the squeezing process; consequently bending curves appear in the outlet lines of the membrane circuit board, aggravated interference with the electrical connections of the electrical connections between the outlet lines and the printed circuit board.
In order to overcome the disadvantage of the prior art, the inventor of the present invention provides an improved elastic strip used in outlet lines of a membrane circuit board to acquire contact with electrical connections of a printed circuit board through a flat surface.